APOLLO 7
The First Mission:
Testing the CSM in Earth Orbit
11 October–22 October 1968
Background
Twenty-one months after the Apollo 1 fire, the United States was ready to begin the piloted phase of the Apollo program. The primary objectives of the first mission were:
The crew members were Captain Walter Marty “Wally” Schirra, Jr. [shi-RAH] (USN), commander; Major Donn Fulton Eisele [EYES-lee] (USAF), command module pilot; and Ronnie Walter “Walt” Cunningham, lunar module pilot.
Selected in the original astronaut group in 1959, Schirra had been pilot of the fifth (third orbital) Mercury mission (MA-8) and command pilot of Gemini 6-A. With Apollo 7, Schirra would become the first person to make three trips into space. Born 12 March 1923 in Hackensack, New Jersey, Schirra was 45 years old at the time of the Apollo 7 mission. Schirra received a B.S. degree from the U.S. Naval Academy in 1945. His backup for the mission was Colonel Thomas Patten Stafford (USAF).
Eisele and Cunningham were each making their first spaceflight. Born 23 June 1930 in Columbus, Ohio, Eisele was 38 years old at the time of the Apollo 7 mission. He received a B.S. in astronautics in 1952 from the U.S. Naval Academy, and an M.S. in astronautics in 1960 from the U.S. Air Force Institute of Technology, and was selected as an astronaut in 1963.[1] His backup was Commander John Watts Young (USN).
Born 16 March 1932 in Creston, Iowa, Cunningham was 36 years old at the time of the Apollo 7 mission. He received a B.A. in physics in 1960 and an M.A. in physics in 1961 from the University of California at Los Angeles. He was selected as an astronaut in 1963. His backup was Commander Eugene Andrew “Gene” Cernan (USN).
The capsule communicators (CAPCOMs) for the mission were Stafford, Lt. Commander Ronald Ellwin Evans (USN), Major William Reid Pogue (USAF)[2], John Leonard “Jack” Swigert, Jr. [SWY-girt], Young, and Cernan. The support crew were Swigert, Evans, and Pogue. The flight directors were Glynn S. Lunney (first shift), Eugene F. Kranz (second shift), and Gerald D. Griffin (third shift).
The Apollo 7 launch vehicle was a Saturn IB, an “uprated” Saturn, designated SA-205. The mission also carried the designation Eastern Test Range #66. The CSM combination was designated CSM-101 and formed the first block II configuration spacecraft flown, that is, with the capability to accommodate the LM and other systems advancements.
Launch Preparations
The countdown began at 19:00 GMT on 6 October 1968. There were three planned holds. The first two, at T-72 hours for six hours and at T-33 hours for three hours, allowed sufficient time to fix any spacecraft problems. The final hold, at T-6 hours, provided a rest period for the launch crew. Six hours later, the clock resumed at 09:00 GMT, 11 October 1968.
The final countdown proceeded smoothly until T-10 minutes when thrust chamber jacket chilldown was initiated for the launch vehicle S-IVB stage. The procedure took longer than necessary and would have required a recycling of the clock to T-15 minutes if the proper temperature were not reached in time for initiation of the automatic countdown sequence. As a result, a hold was called at T-6 minutes 15 seconds, and lasted for 2 minutes 45 seconds. Postlaunch analysis determined that chilldown would have occurred without the hold, but the hold was advisable in real-time to meet revised temperature requirements. At 14:56:30 GMT, the countdown resumed and continued to liftoff without further problems.
A large high pressure system centered over Nova Scotia caused high easterly surface winds at launch time. The upper winds, above 30,000 feet, were light from the west. Surface wind speeds were the highest observed for any Saturn vehicle to date. A few scattered clouds were in the area. Cumulonimbus clouds covered 30 percent of the sky with a base at 2,100 feet, visibility 10 statute miles, temperature 82.9° F, relative humidity 65 percent, dew point 70.0° F, barometric pressure 14.765 lb/in2, and winds 19.8 knots at 90° from true north measured by the anemometer on the light pole 59.4 feet above ground at the launch site.
Ascent Phase
Apollo 7 was launched from Launch Complex 34 at Cape Kennedy, Florida (USAF Eastern Test Range). Liftoff occurred at a Range Zero time of 15:02:45 GMT (11:02:45 a.m. EDT) on 11 October 1968, well within the planned launch window of 15:00:00 to 19:00:00 GMT.
The ascent phase was nominal. Moments after liftoff, the vehicle rolled from a launch pad azimuth of 100° to a flight azimuth of 72° east of north. The first stage provided continuous thrust until center engine cutoff at 000:02:20.65. The outboard engine shut down 3.67 seconds later at an Earth-fixed velocity of 6,479.1 ft/sec. Cutoff conditions were very close to prediction.
The S-IB was separated from the upper stage at 000:02:25.59, followed by S-IVB engine ignition at 000:02:26.97. Cutoff occurred at 00:10:16.76, with deviations from the planned trajectory of only 2.3 ft/sec in velocity and 0.054 n mi in altitude. The S-IVB burn time of 469.79 seconds was within one second of prediction, and all structural load limits were well within design tolerances during ascent.
The maximum wind conditions encountered during ascent were 81 knots at 172,000 feet. Wind shear in the high dynamic pressure region reached 0.0113 sec-1 in the pitch plane at 48,100 feet. The maximum wind speed in the high dynamic pressure region was 30.3 knots from 309° at 44,500 feet.
The probable impact of the spent S-IB was determined from a theoretical, tumbling, free flight trajectory. Assuming the booster remained intact during entry, the impact occurred in the Atlantic Ocean at latitude 29.76° north and longitude 75.72° west, 265.01 n mi from the launch site.
At 000:10:26.76, the spacecraft entered Earth orbit, defined as S-IVB cutoff plus 10 seconds to account for engine tailoff and other transient effects. At insertion, conditions were: apogee and perigee 152.34 by 123.03 n mi, inclination 31.608°, period 89.55 minutes, and velocity 25,532.2 ft/sec. The apogee and perigee were based upon a spherical Earth with a radius of 3,442.934 n mi.
The international designation for the spacecraft upon achieving orbit was 1968-089A and the S-IVB was designated 1968-089B.[3]
Inflight Activities
The crew adapted quickly and completely to the weightless environment. There were no disorientation problems associated with movement inside the CM nor looking out the windows at Earth. In fact, an attempt by the lunar module pilot to induce vertigo or motion sickness by movement of the head in all directions at rapid rates met with negative results. Early in the mission, however, the crew reported some soreness of their back muscles in the kidney area. The soreness was relieved by exercise and hyperextension of the back.
Prior to separation from the S-IVB, a 2-minute 56-second manual takeover of attitude control from the launch vehicle stage was performed at 002:30:48.80. The crew exercised the manual S-IVB/IU orbital attitude control capability. This consisted of a test of the closed loop spacecraft/launch vehicle control system by performing manual pitch, roll, and yaw maneuvers. The control system responded properly. After completion of the test, the crew switched attitude control back to the automatic launch vehicle system which resumed the normal attitude timeline. By the time the CSM/S-IVB separated at 002:55:02.40, venting of S-IVB propellants had raised the orbit to 170.21 by 123.01 n mi.
One objective of Apollo 7 was to perform a “safing” of the S-IVB stage by lowering pressure in the propellant tanks and high-pressure bottles to a level that would permit safe rendezvous and simulated docking maneuvers. The safing was scheduled to take place in several stages. First, the LH2 tank safing was to be performed by three pre-programmed ventings; however, four additional ventings were required because the pre-programmed ones did not adequately safe the tank under the orbital conditions experienced. The first venting occurred at 000:10:17, and the final one ended at 005:11:15. The seven ventings totaled 3,274.1 seconds. Second, a liquid oxygen dump was initiated at 001:34:28 and lasted 721.00 seconds. Third, a cold helium dump was performed at 001:42:28 and again at 004:30:16, lasting 2,868.00 and 1,199.99 seconds, respectively. Finally, a stage control sphere helium dump occurred at 003:17:33, but was terminated by ground command after 2,967 seconds to save the remaining helium for control of the LH2 tank vent-and-relief valve. Safing, however, was adequately accomplished.
During the second revolution the crew observed that one of the spacecraft/LM adapter panels on the S-IVB was deployed only 25° instead of the normal 45°. It had opened fully, but a retention cable designed to prevent the panel from closing had become stuck and the panel had partially closed. This was not a problem because the panels would be jettisoned on future missions. By the 19th revolution, the panel had moved to the full open position.
In order to establish conditions required for rendezvous with the S-IVB, a 16.3-second phasing maneuver was performed at 003:20:09.9 using the service module reaction control system. This resulted in an orbit of 165.2 by 124.8 n mi.
The phasing burn was intended to place the spacecraft 76.5 n mi ahead of the S-IVB. However, the S-IVB orbit decayed more rapidly than anticipated during the six subsequent revolutions. An additional phasing maneuver of 17.6 seconds was performed at 015:52:00.9 to obtain the desired conditions. The resulting orbit was 164.7 by 120.8 n mi.
At 014:46, it was reported that the commander had developed a bad head cold, which had begun about one hour after liftoff, and that he had taken two aspirins. The next day, the other two crew members also experienced head cold symptoms. This condition, which continued throughout the mission, caused extreme discomfort because it was very difficult to clear the ears, nose, and sinuses in “zero g” conditions. Medication was taken, but the symptoms persisted.
At 023:33, the spacecraft commander canceled the first television transmission, scheduled to begin in 20 minutes. Annoyed that mission control had added two burns and a urine dump to the crew’s workload while they were testing a new vehicle, and still suffering from a cold, Schirra reported that, “...TV will be delayed without further discussion...”
Two service propulsion system firings were required for rendezvous with the S-IVB. The first firing, a 9.36-second corrective combination maneuver at 026:24:55.66, was necessary to achieve the desired 1.32° phase and 8.0 nautical mile altitude offset so that the second firing would produce an orbit coelliptic with that of the S-IVB. The result was an orbit of 194.1 by 123.0 n mi. During this period, the sextant was used to track the S-IVB, which was visible in reflected sunlight. The 7.76-second firing at 028:00:56.47 occurred when the spacecraft was 80 n mi behind and 7.8 n mi below the S-IVB, and created a more circularized orbit of 153.6 by 113.9 n mi.
The two firings achieved the desired conditions for the 46-second rendezvous terminal phase initiation, which occurred at 029:16:33, about four and one half minutes earlier than planned because of a minor variation in the orbit. A small midcourse correction was made at 029:37:48, followed by a 708-second braking maneuver at 029:43:55, and final closure to within 70 feet of the tumbling S-IVB. Stationkeeping was performed for 25 minutes starting at 029:55:43 in an orbit of 161.0 by 122.1 n mi, after which a 5.4-second service module reaction control system posigrade maneuver removed the CSM from the vicinity of the S-IVB stage. The crew maneuvered the CSM around the S-IVB in order to inspect and photograph it.
The rendezvous maneuver was important because it demonstrated the ability of the spacecraft to rendezvous with the LM (represented by the S-IVB) if the ascent stage became disabled after leaving the lunar surface. However, the crew reported that the manually-controlled braking maneuver was frustrating because no reliable backup ranging information was available, as would be the case during an actual rendezvous with the LM.
The next 24-hour period was devoted to a sextant calibration test at 041:00, two attitude control tests at 049:00 and 050:40, and two primary evaporator tests at 049:50 and 050:30. In addition, the crew performed a rendezvous navigation test, using the sextant to track the S-IVB visually to a distance of 160 n mi at 044:40 and to 320 n mi at 053:20. The crew later reported sighting the S-IVB at a range of nearly 1,000 n mi.
To ensure maximum return from Apollo 7, it was planned to complete as many primary and secondary objectives as possible early in the flight, and, by the end of the second day, more than 90 percent had been accomplished.
Three tests of the rendezvous radar transponder were performed. This system would be essential for docking the LM ascent stage to the CM after liftoff from the lunar surface. The first two tests occurred at 061:00 and 071:40. The third was performed during revolution 48 at 076:27, when the ground radar at White Sands Missile Range, New Mexico, acquired and locked onto the spacecraft transponder at a range of 390 n mi and tracked it to 415 n mi.
At 071:43, the first of seven television transmissions began and lasted for seven minutes. It was the first live television transmission from a piloted American spacecraft. The crew opened the telecast with a sign that read “From the lovely Apollo room high atop everything.” They then aimed the camera out the window as the spacecraft passed over New Orleans and then over the Florida peninsula. The orbital motion of the spacecraft was evident.
The service propulsion system was fired six additional times during the mission. The third firing, at 075:48:00.27 (advanced 16 hours from the original plan), was a 9.10-second maneuver controlled by the stabilization and control system. The maneuver was performed early to increase the backup deorbit capability of the service module reaction control system by lowering the perigee to 90 n mi and placing it in the northern hemisphere. The resulting orbit was 159.7 by 89.5 n mi.
After the third firing, a three-hour cold soak of the service propulsion thermal control system was performed. The cold soak stabilized the spacecraft and exposed one side away from the Sun for a period of time to lower the temperature and monitor the effects of the cold space environment. The thermal characteristics of the system were better than anticipated for random, drifting flight, because the temperature decrease was less than predicted.
A test to determine whether the environmental control system radiator surface coating had degraded was conducted between 092:37 and 097:00. Results indicated that the solar absorptivity of the radiator panel tested was within predicted limits, and validated the system for lunar flight.
The second television transmission started at 095:25 and lasted about 11 minutes. The program included a tour of the CM including various controls, a demonstration of the exercise device, and an attempt to show water condensation inside the spacecraft.
Condensation was a major problem associated with the cabin and suit circuits. This problem was anticipated in the cabin because the cold coolant lines from the radiator to the environment control unit and from the environment control unit to the inertial measurement unit were not insulated. Each time excessive condensation was noted on the coolant lines or in a puddle on the aft bulkhead after service propulsion system maneuvers, the crew vacuumed the water overboard. Experiment S005 (Synoptic Terrain Photography) began at 098:40, using a hand-held modified 70 mm Hasselblad 500C camera. The photographs were used to study the origin of the Carolina bays in the United States, wind erosion in desert regions, coastal morphology, and the origin of the African rift valley. Near-vertical, high-sun-angle photographs of Baja California, other parts of Mexico, and parts of the Middle East were useful for geologic studies. Photographs of New Orleans and Houston were generally better for geographic urban studies than those available from previous programs.
Areas of oceanographic interest, particularly islands in the Pacific Ocean, were photographed for the first time. In addition, the mission obtained the first extensive photographic coverage of northern Chile, Australia, and other areas. Of the 500 photographs taken of land and ocean areas, approximately 200 were usable, and, in general, the color and exposure were excellent. The need to change the film magazines, filters, and exposure settings hurriedly when a target came into view, and to hold the camera steady, accounted for the improper exposure of many frames.
The purpose of Experiment S006 (Synoptic Weather Photography) was to photograph as many as possible of 27 basic categories of weather phenomena, and began at 099:10. The camera was the same used for Experiment S005. Of the 500 photographs taken, approximately 300 showed clouds or other items of meteorological interest, and approximately 80 contained features of interest in oceanography. Categories considered worthy of additional interest included weather systems, winds and their effects on clouds, ocean surfaces, underwater zones of Australian reefs, the Pacific atolls, the Bahamas and Cuba, landform effects, climactic zones, and hydrology. Oceanographic surface features were revealed more clearly than in any of the preceding piloted flights. The photographs of Hurricane Gladys and Typhoon Gloria, taken on 17 October and 20 October 1968, respectively, were the best-to-date views of tropical storms. Image sharpness of photographs for this experiment ranged from fair to excellent, again affected by the difficulty in holding the camera steady. Regardless, ocean swells could be resolved from altitudes near 100 n mi.
The third television transmission began at 119:08 and lasted about ten minutes. It featured a demonstration of how to prepare food in space, in particular a package of dried fruit juice reconstituted with water. The telecast also showed the process of vacuuming water that had accumulated on the cold glycol lines. Various controls at the commander’s workstation were also viewed.
The fourth service propulsion system firing, at 120:43:00.44, was performed to evaluate the minimum-impulse capability of the service propulsion engine. It lasted only 0.48 seconds and produced an orbit of 156.7 by 89.1 n mi.
A tour of the CM, the fourth television transmission, began at 141:11. The crew trained their camera on deposits on window 1 and on optical site markings used to measure pitch angle on window 2. Panning around the spacecraft, the camera gave viewers a look at sleep stations, stowage areas, helmet bags and pressure suit hoses. The commander also demonstrated weightlessness by blowing on a floating pen to control its motion. By 141:27, the crew had signed off and the transmission signal had faded.
During this time, the S-IVB stage continued to orbit the Earth. It impacted the Indian Ocean at 09:30 GMT on 18 October during the 108th revolution of the Earth. The estimated impact point was latitude 8.9° south and longitude 81.6° east at 162:27:15.
A fifth service propulsion system firing was performed to position the spacecraft for an optimum deorbit maneuver at the end of the planned orbital phase by allowing at least two minutes of tracking by the Hawaii ground station if another orbit were required. This occurred at 165:00:00.42. To ensure verification of the propellant gauging system, the firing duration was increased from the original plan.
The 66.95-second maneuver produced the largest velocity change of the mission, 1,691.3 ft/sec, and incorporated a manual thrust-vector-control takeover halfway through the maneuver. The resulting orbit was 244.2 by 89.1 n mi.
During translunar and transearth flight on future missions, it would be necessary to put the spacecraft into a slow “barbecue” roll to maintain an even external temperature. This maneuver, called passive thermal control, was tested twice on Apollo 7, first at 167:00 and next at 212:00.
The fifth television transmission, starting at 189:04, featured another spacecraft tour. The program began with a view of the instrument panel including attitude thruster switches and the display keyboard, and cryogenic controls, and ended with the crew performing a military “close order drill.” An attempt to show scenes of Earth was unsuccessful.
The sixth SPS firing was performed during the eighth day, at 210:07:59.99, and was the second minimum-impulse maneuver. At the time, the apogee was 234.6 n mi and the perigee was 88.4 n mi. This firing lasted 0.50 seconds and was directed out-of-plane because no change in orbit was desired.
For the sixth television transmission, starting at 213:10, the crew aimed the camera out the window and gave ground controllers a view of the Florida peninsula. They then turned the camera inside the spacecraft to show off the beards they had grown during the mission.
At 231:08, the Solar Particle Alert Network facility at Carnarvon, Australia, detected a Class 1B solar flare. Analysis of data confirmed the flare would have no effect on the spacecraft or crew. However, this exercise proved to be an excellent checkout of the systems and procedures that would be used in the event of a solar flare during a lunar mission. This event was followed by the seventh service propulsion system firing, a 7.70-second maneuver at 239:06:11.97, which placed the spacecraft perigee at the proper longitude for entry and recovery, and lowered the orbit to 229.8 by 88.5 n mi.
For the final television transmission, starting at 236:18 and lasting for about 11 minutes, the crew showed off their beards again, and reported seeing several jet contrails far below them over the Gulf Coast. They also described the bands of color created by the day air glow above the Earth.
The midcourse navigation program, using the Earth horizon and a star, could not be accomplished because the Earth horizon was indistinct and variable. The air glow was about three degrees wide and had no distinct boundaries or lines when viewed through the sextant. This problem seemed to be associated with the spacecraft being in a low Earth orbit. Using this same program on lunar landmarks and a star, however, the task was very easy to perform. Lunar landmarks showed up nearly as well as Earth landmarks. Stars could be seen at 10° and 15°, and greater, from the Moon.
Sextant/star counts and star checks and star/horizon sightings were made throughout the mission; lunar landmark/star sightings were attempted at 147:00.
Recovery
The final day of the mission was devoted primarily to preparations for the deorbit maneuver. This was accomplished by the eighth SPS firing, an 11.79-second eighth service maneuver at 259:39:16.36 over Hawaii, during the 163rd orbit. During the final orbit, the apogee was 225.3 n mi, the perigee was 88.2 n mi, the period was 90.39 minutes, and the inclination 29.88°.
Because of their cold symptoms, there was a considerable amount of discussion about whether the crew should wear helmets and gloves during entry. With helmets on, it might be impossible to properly clear the throat and ears as increasing gravity drew mucus down from the head area, where it remained during zero gravity conditions. It was decided 48 hours prior to entry, and at the crew’s insistence, that helmets and gloves would not be worn.
The service module was jettisoned at 259:43:33, and the CM entry followed both automatic and manually guided profiles. The command module reentered the Earth’s atmosphere (400,000 feet altitude) at 259:53:26 at a velocity of 25,846.4 ft/sec. Trajectory reconstruction indicated that the service module impacted the Atlantic Ocean at 260:03 at a point estimated to be latitude 29° north and longitude 72° west. During entry, three objects—the CM, the service module, and a 12-foot insulation disk between the two—were tracked simultaneously and were also sighted visually.
The parachute system effected a soft splashdown of the CM in the Atlantic Ocean southeast of Bermuda at 11:11:48 GMT (07:11:48 a.m. EDT) on 22 October 1968. Mission duration was 260:09:03. The impact point was 1.9 n mi from the target point and 7 n mi from the recovery ship U.S.S. Essex. The splashdown site was estimated to be latitude 27.63° north and longitude 64.15° west. After splashdown, the CM assumed an apex-down flotation attitude, but was successfully returned to the normal flotation position within 13 minutes by the inflatable bag uprighting system. During this period, the recovery beacon was not visible and voice communication with the crew was interrupted.
The crew was retrieved by helicopter and was aboard the recovery ship 56 minutes after splashdown. The CM was recovered 55 minutes later. The estimated CM weight at splashdown was 11,409 pounds, and the estimated distance traveled for the mission was 3,953,842 n mi.
At CM retrieval, the weather recorded onboard the Essex showed light rain showers, 600-foot ceiling; visibility 2 n mi; wind speed 16 knots from 260° true north; air temperature 74° F; water temperature 81° F; with waves to 3 feet from 260° true north.
The CM was offloaded from the Essex on 24 October at the Norfolk Naval Air Station, Norfolk, Virginia, and the Landing Safing Team began the evaluation and deactivation procedures at 14:00 GMT. Deactivation was completed at 01:30 GMT on 27 October 1968. The CM was then flown to Long Beach, California and trucked to the North American Rockwell Space Division facility at Downey, California for postflight analysis.
Conclusions
The Apollo 7 mission was successful in every respect. All spacecraft systems operated satisfactorily, and all but one of the detailed test objectives were met. As an engineering test flight, Apollo 7 demonstrated the performance of the orbital safing experiment, the adequacy of attitude control in both the manual and automatic modes, and that the vehicle systems could perform for extended periods in orbit. For the first time, a mixed cabin atmosphere consisting of 65 percent oxygen and 35 percent nitrogen was used aboard an American piloted spacecraft. All previous flights had used 100 percent oxygen, a procedure changed as a result of recommendations made by the Apollo 1 fire investigation board. Another “first” was the availability of hot and cold drinking water for the crew as a by-product of the service module fuel cells, an important element for piloted lunar excursions. Consumables usage was maintained at safe levels, and permitted the introduction of additional flight activities toward the end of the mission.
The most significant aerodynamic effect encountered was the unexpected phenomenon noted as “perigee torquing,” a rotation of the CSM most noticeable when the perigee was at 90 n mi.
The following conclusions were made from an analysis of post-mission data:
a. Onboard navigation using the landmark tracking technique proved feasible in Earth orbit.
b. The Earth horizon was not usable for optics measurements in low Earth orbit with the available optics design and techniques.
c. Although a debris cloud of frozen liquid particles following venting obscured star visibility with the scanning telescope, it could be expected to dissipate rapidly in Earth orbit without significantly contaminating the optical surfaces.
d. Star visibility data with the scanning telescope indicated that in cislunar space, with no venting and with proper spacecraft orientation to shield the optics from the Sun and Earth or Moon light, constellation recognition would be adequate for platform inertial orientation.
e. Sextant star visibility was adequate for platform realignments in daylight using Apollo navigation stars as close as 30° from the Sun line-of-sight.
[1] Eisele died of a heart attack 1 December 1987 in Tokyo, Japan (Houston Chronicle, 3 Dec 1987, p. 8).
[2] Pogue replaced Major Edward Galen Givens, Jr. (USAF), who died in an automobile accident in Pearland, TX, on 6 June 1967. Givens had been selected in the astronaut class of 1966 (Houston Chronicle, 8 Jun 1967).
[3] RAE Table of Earth Satellites 1957-1986, pages vii, and viii. The international Committee on Space Research (COSPAR) has given all satellites a designation based on the year of launch (first four digits) and number of successful launches during that year (next three digits). In COSPAR terminology, the letter A usually refers to the instrumented spacecraft, B to the rocket, and C, D, E, etc. to fragments.